This scheme has been prepared to guide the construction and to meet the requirements of the quality regulations.
Basis of preparation
Basis of preparation: concrete structure construction specifications, construction design requirements, P&G requirements.
Construction focus and difficulties
- Ground elevation control
- Ground flatness control
- Night work and rain protection measures
- Finished product protection
Concrete industrial floor construction methods
- To prevent hollowing out of the industrial floor, the surface layer of the mat should be cleaned to remove slicks and oil stains; the substrate should be moistened with water.
- Ground concrete grade C30. 3.
- The slump of freshly poured concrete should be controlled between 10-300px when using commercial concrete.
- The mud content of freshly poured concrete aggregate should be controlled within 1%, and the maximum aggregate size should be controlled within 75px. 5) Freshly poured concrete should be used with power-activated concrete.
- freshly poured concrete should be pounded with power screed or laser screed, at the part that cannot be compacted by roller, the wooden crab can be used first, then power screed for leveling.
- excess water secretion on the concrete surface should be removed in time, during construction, excess water secretion can be absorbed with a leather tube, or absorb and transfer excess water secretion with a sponge.
Technical requirements for flooring construction
- Removal of floating slurry
The surface of freshly poured concrete has a lot of floating slurry, which must be cleaned off during construction so as not to affect the quality of the ground. When the newly poured concrete has set for the first time (that is to say, it sinks without sinking), grind off the floating pulp layer on the surface of the concrete evenly with a power trowel fitted with a disc.
- Pulp lifting and surface finish
Use power trowel or ride on power trowel equipped with the disc to press grinding and lifting slurry according to the order of spreading, and press grinding and lifting slurry by power trowel vertically and horizontally at least twice during construction; as for columns, walls and other parts near edges and corners where it is not easy to press grinding by machinery, you can directly press grinding and lifting slurry by the bull float.
After finishing the ground slurry construction, depending on the hardening condition of the concrete, after the surface of the ground is getting dull, you can carry out the surface layer lightening construction, using power trowel to lighten at least three times, the running speed of power trowel and the change of blade angle should be adjusted according to the hardening condition of the ground concrete. Adjust the angle of the blades once at the beginning of each finish to avoid damage to the flooring. This is the final finishing operation for the flooring, so it is important to select personnel with a high level of responsibility and skill.
Mechanical work can not handle the part of the manual calendering treatment with bull float, the construction of manual light harvesting should be slightly earlier than the mechanical, the work does not allow the appearance of traces of blister and light harvesting, and keep the joints smooth. To ensure the construction quality of the entire industrial floor.
- Maintenance of the flooring
Subsequent maintenance is directly related, especially when working in warmer weather. In order to ensure stable growth of the strength of the concrete flooring, 5-6 hours after the completion of the construction of the flooring, you can carry out maintenance, flooring maintenance can be used on the surface of the method of applying maintenance agent, or directly with water or with a film covering the method of maintenance, flooring maintenance time should generally be not less than 7 days. During maintenance, the flooring surface should be protected from oil, mortar, dyes, corrosive liquids, etc. during construction by other trades, and protective facilities should be added to equipment that must pass over the flooring surface. During the maintenance period, it is prohibited to carry heavy loads and cross-work on the surface of the flooring.
Concrete Ground Leveling Control
- Levelness design requirements
The floor of the production workshop in this project is required to be polished with vibrating, and the flatness is strictly ensured, and the height difference should not be greater than 3mm with a 3m ruler.
- Construction preparation requirements
The work must be carried out by skilled concrete workers, who must be clear about the contents of the handover and grasp the essentials before the work begins. Personnel, materials, implements, temporary electricity, fences, and other preparatory work must be done before construction.
- Pouring order:
Natural division into blocks according to the cast-in-band, with pouring between the blocks in pairs or at intervals on the same side.
- Zero plate elevation control setting and flatness control
Bedding construction, bolt angle iron fabrication → bolt and angle iron installation → elevation reading and surveying → concrete pouring and leveling → angle iron dismantling and secondary leveling → maintenance → inspection and acceptance
Use specific elevation control bolts, together with angle irons for elevation control, with a distance of 3m between the angle irons during construction, using 6m leaning feet and leveling according to the preset elevation.
Determine the distance between the angle irons and their support points
After due consideration of the stiffness properties of the L30 angle iron and the amount of material used, we decided to set the support points on the 6m long angle iron at 1900mm intervals.
We consulted with the construction team and, in conjunction with the ease of use by the builders, decided on spacing of 3m between the angle irons.
Development of the fixing method for the mediation bolts
After discussion among the QC team members, it was decided that the sample would be placed on the pad first, then the Φ12 drill bit would be used to drill the holes in the release position, and the Φ14 adjustment bolts would be nailed into the concrete pad. During construction, if the bolts were loose, they were reinforced with nails in the gap between the bolts and the holes.
Leveling of the angle iron with a spirit level
During the construction, the technician leveled the angle iron with a C32II level, at the same time, the builder adjusted the adjusting nut according to the technician’s instructions, adjusted the height of the angle iron, and tightened the fixing nut after checking. During the leveling process, the elevation of each adjustment point was carefully calibrated. As shown on the right.
Concrete leveling with 6m leveling feet
The concrete was poured after the elevation points had been verified. After the concrete had been paved, the concrete surface was leveled by three men simultaneously using a 6m leaning rod along a “track” made up of angle irons. Concrete protruding from the ground elevation is scraped out, while depressions are repaired by another person, and then leveled again by the three leveling men.
Removal of angle iron
After the concrete has been poured and leveled, remove the angle iron when the concrete starts to set. Use a ruler to level the concrete surface again along the formed concrete surface in the area of the angle iron. Clean the angle iron for turnover at the same time.
Use aluminum alloy square pass to level the concrete along the surface of the angle iron, at least 2 to 3 times. The first time with 3-5m long aluminum alloy square leveling, in the process of leveling for the poor material where to be added with the rush, in the concrete is close to the initial set and above the basic can take off the angle steel, beyond the concrete finished surface of the support steel bent with a steel handle and buried in the concrete. In the process of fine leveling, where the small error cannot be added to the concrete, level it with 1:1 cement dry mortar, and after leveling, grind the whole of the lifting pulp machine to lift the pulp once again, and when the lifting pulp is finished, level it with the aluminum alloy square. When the concrete is first set, use a polishing machine to collect light in a large area, and adopt manual calendering treatment in advance for the corners because the machine cannot be in place.
In the process of second time leveling, surveyors must set up-leveling instrument to detect the flatness error in the whole process, in order to ensure the flatness, every 1m or so must measure a point, and deal with the part that exceeds the standard in time during the measuring process.
- Protection of finished concrete slabs
(1) Take responsibility for the management of the zone, who is responsible for the operation, and set up supervisors to follow up and check the protection of the finished products in the operation area every day, and order rectification in time when violations are found.
(2) As for operations with heavy objects that are likely to cause injury to the ground, wooden boards must be laid on the ground before construction.
(3) For operations that are likely to cause ground pollution but do not have heavy objects, colorful strips of cloth must be laid on the ground to protect it from pollution before construction.
(4) For operations that are polluting and have heavy objects, colorful strips of cloth must be laid before the construction of the wooden plate before the work can be carried out.
- 6. Concrete curing
(1) 24 hours after concrete pouring is completed, water is used to cover the plastic film for water conservation maintenance.
(2) In order to ensure the quality of flooring maintenance, adopt special personnel to sprinkle water for maintenance. Sprinkling should be done frequently and sparingly, and the water used for maintenance should be the same as that used for mixing.
(3) The curing period should not be less than 21 days, and measures should be taken to protect the poured concrete from the damage of upper construction.
(4) Do not step on or install formwork and supports on concrete until its strength reaches 1.2N/mm2.
Concrete industrial floors at night and rainproofing measures
Night work measures
- If the concrete construction is scheduled to be poured at noon, the leveling and glazing will be carried out at night.
- 2. Adequate lighting fixtures should be available before the night work.
- 3. If you are notified of power failure, no concrete construction will be arranged.
- Keep the construction channel clear.
- Arrange for managers to be on duty
- Arrange for electricians, reinforcement workers and carpenters to be on duty.
- Prepare construction materials and implements in advance.
- As flooring concrete is an open-air operation, it is necessary to ensure that the construction of flooring concrete will not be affected by rain, keep track of the weather conditions and avoid construction on rainy days.
- In the case of temporary showers, take the following rainproof measures before construction to prepare rainproof materials.
Prepare 700 square meters of rainproof tarpaulin, set up temporary rainproof shelters, and protect the poured ground.
Protection of finished concrete industrial floors
- to the completed ground should be timely set up the finished protective fence, in the personnel frequent access to the door hanging eye-catching protection signs, prohibit personnel to enter the maintenance period of the flooring, and assign someone responsible for care.
- before the steel structure is lifted, the flooring is protected against impact by covering the film, full of geotextile and densely paved with 18-thick wood formwork.
- When welding steel structures, fire-fighting measures are taken, including the setting of fire extinguishers, the supervision of welding fires by safety personnel, and the use of colorful steel plates as partitioning measures underneath the fires.
4.For electromechanical installation, arrange the position of inlet and outlet of water to avoid the flow of test water into the flooring when the electromechanical is being tested by hydraulic pressure, and at the same time place a receiving bucket at the joint position to prevent pollution caused by leakage of water into the ground.